Conventionally, in the field of manufacture of semiconductor devices, LCD devices and the like, there has been used a plasma processing apparatus for performing plasma etching or plasma CVD by generating a plasma. In such plasma processing apparatus, the plasma is generated by creating a depressurized atmosphere in a processing chamber, wherein an electrostatic chuck has been widely employed as means for sustaining a target substrate in the vacuum chamber.
As the aforementioned electrostatic chuck, there is known one having an electrode embedded in an insulating film, wherein a thermally sprayed film is used as the insulating film. Further, there is also known a technique that employs a spray material containing a substance whose volume is expanded when it is thermally sprayed on a base member such as copper-based powder that undergoes a martensite transformation, thereby enhancing the adhesivity of the thermally sprayed material to the base member, while preventing it from being detached therefrom (see, for example, Japanese Patent Laid-open Application No. H10-68058: Patent Reference 1).
FIG. 4 provides an enlarged configuration view of major parts of such an electrostatic chuck. Reference numeral 200 denotes a base member made of aluminum or the like. A thermally sprayed insulating film 210 is formed on the top surface (mounting surface for mounting a target substrate thereon) of the base member 200, and an electrostatic chuck electrode 211 is embedded in the thermally sprayed film 210. Further, the base member 200 is provided with a circular hole 201 through which a lifter pin (not shown), which serves as a substrate supporting member for sustaining the target substrate on the mounting surface, is installed, and cylindrical sleeves 220 made of insulating ceramic or the like are provided inside the circular hole 201. The sleeves 220 cover the inside of the circular hole 201 to insulate it and serve to prevent the lifter pin from rubbing against the inner surface of the circular hole 201 to thereby suppress dusts being generated when it is moved up and down.
In such a substrate mounting structure having the configuration shown in FIG. 4 for use in the plasma processing apparatus, the temperature of the base member 200 is controlled by means of a temperature control mechanism so that the temperature of the target substrate mounted on the substrate mounting structure is regulated at a desired temperature level suitable for a plasma process. Recently, some plasma processes are performed at a high temperature of, for example, 100° C. or higher. If the plasma process is performed at such a high temperature, however, the thermally sprayed film 210 can be damaged, resulting in a failure of the insulation of the electrostatic chuck 211 or the base member 200. As a result, an electric discharge or the like can be caused.